The Source and the Goal

to prepare God's people for works of service, so that the body of Christ may be built up until we all reach unity in the faith and in the knowledge of the Son of God...
Instead, speaking the truth in love, we will in all things grow into him who is the Head, that is Christ.
Ephesians 4:12-13a & 15
The unity of God's church is beyond important, so much so that it was one of the last things Jesus prayed for before he died. Here in Ephesians, we get a glimpse of two very practical ways to work towards this:
  1. Serve

  2. Speak the truth in love

Jesus exemplified both of these in His day-to-day service of the disciples (i.e. - washing their feet), and His often hard, but true, words to His disciples (i.e. - telling Peter, "Get behind me Satan!"). In examining His life, we have both the key and the goal to fulfilling God's purpose in this matter: knowing Jesus. that the body of Christ may be built up until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ. (Ephesians 4:12-13)
Unity in the faith and in the knowledge of the Son of God -- the entire goal of God's church is summed up in this verse -- God wants us to believe in and know God's Son. God's purpose for us is more than faith in Him for salvation, but rather that we know Him. Love Him. Be loved by Him.
On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’ And then will I declare to them, ‘I never knew you; depart from me, you workers of lawlessness.’ (Matthew 7:22-23)
That verse always scared me because it features a lot of people who did seemingly big things for God, but then Jesus will not allow them into His kingdom because they do not know Him. If this is the case, investing time and energy into our practical relationship with God must take precedence over everything, even our works in ministry. And here is why:
I pray that out of his glorious riches he may strengthen you with power through his Spirit in your inner being, so that Christ may dwell in your hearts through faith. And I pray that you, being rooted and established in love, may have power, together with all the saints, to grasp how wide and long and high and deep is the love of Christ, and to know this love that surpasses knowledge -- that you may be filled to the measure of all the fullness of God. (Ephesians 3:16-19)
Notice the order of things there: we are strengthened with power through the Spirit within us (Who is there only because of Christ's sacrifice), so Christ can dwell in our hearts (love). Then, with love as our foundation, we may have the power (together with the church) to understand Christ's love. Love leads to power leads to love. Only through a connection to Christ's love can we even have the power to understand his love better, leading to a fuller knowledge of Him.
Love is both our source and our goal. And this is the "fullness of God," His purpose for us as His church.